Prediction of pathological subtrochanteric fractures due to metastatic lesions.

We report a radiographic review of 54 consecutive patients with 24 impending and 30 actual pathological fractures due to metastatic bone lesions in the subtrochanteric femoral region. In an attempt to develop criteria for metastatic lesions at risk of fracturing, the following variables based on anteroposterior and lateral X-rays were considered: appearance of the lesion, width of the lesion, ratio between width of the lesion and bone width, length of the lesion, length of cortex involvement, proportion of transverse cortical bone destroyed and local pain. Nearly all (99%) of the lesions were radiographically classified as lytic. In 27 cases (50%) they were radiographically unmeasurable. Maximal longitudinal cortical destruction showed a difference between patients with an actual or impending fracture. Prophylactic internal fixation of pathological subtrochanteric fractures due to metastatic lesions has to be considered in cases of increasing pain. If the conventional X-ray can not be evaluated, a computed tomography (CT) scan has to be considered.